Hexspeak is the practice of spelling words using only the sixteen hexadecimal digits 0 to 9 and A to F, optionally swapping some letters for lookalike digits. Famous examples include DEADBEEF and CAFEBABE, which programmers use as recognisable magic numbers in memory.

Which letters can be encoded?

The letters a to f are already hex digits, so they stay. Others are mapped to lookalike digits: i and l become 1, o becomes 0, s becomes 5, t becomes 7, z becomes 2, and g becomes 6.

What if a word contains a letter with no hex equivalent?

Letters such as h, j, k, m, n, p, q, r, u, v, w, x and y have no hexadecimal lookalike. They are kept visible but the tool flags the word as not valid hex and lists which letters could not be mapped.

Why does it show a decimal value?

When a word encodes to valid hexadecimal, the tool interprets it as a number and shows its base-ten value. This is how DEADBEEF becomes the constant 3735928559 used in real software.

Is my text uploaded anywhere?

No. The encoding runs entirely in your browser, so nothing is sent to a server.

What is the Hexspeak Word Encoder?

Free hexspeak encoder — turn words into hexadecimal-readable strings like DEADBEEF and CAFEBABE, with live hex-validity and decimal-value checks. Runs in your browser. It runs free in your browser on Gera Tools, with nothing uploaded.

Hexspeak Word Encoder

Name: Hexspeak Word Encoder
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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Hexspeak is a programmer in-joke: spelling words using only hexadecimal digits so they can double as memorable magic numbers in code. DEADBEEF, CAFEBABE, BAADF00D and 0xC0FFEE are all real constants that have been used to mark uninitialised memory or tag file formats. This tool turns your words into hexspeak and tells you whether the result is genuinely valid hex.

How it works

Hexadecimal uses sixteen symbols: the digits 0 to 9 and the letters A to F. The letters a through f map straight onto themselves. For the rest, hexspeak relies on visual lookalikes. This tool applies the common substitutions: i and l become 1, o becomes 0, s becomes 5, t becomes 7, z becomes 2, and g becomes 6. Existing digits in your input are kept as-is.

After substitution the tool checks whether every character in the word is a valid hex digit. If so, the word is a true hexadecimal number, and the tool also shows its decimal value by interpreting the string as base 16. Letters with no hex lookalike — h, j, k, m, n, p, q, r, u, v, w, x, y — are kept visible but flagged, since they break hex validity.

The substitution table

Input letter	Hex substitution	Rationale
a	A	Already a hex digit
b	B	Already a hex digit
c	C	Already a hex digit
d	D	Already a hex digit
e	E	Already a hex digit
f	F	Already a hex digit
g	6	Looks like 6
i, l	1	Both look like 1
o	0	Looks like zero
s	5	Looks like 5
t	7	Looks like 7
z	2	Looks like 2

Classic examples

dead  -> DEAD      valid hex (= 57,005)
beef  -> BEEF      valid hex (= 48,879)
cafe  -> CAFE      valid hex (= 51,966)
decade-> DECADE    valid hex (= 14,601,950)
goose -> 60052     valid hex (= 393,298)
facade-> FACADE    valid hex (= 16,435,934)
hello -> HE110     not valid hex (can't map: h)

Where hexspeak appears in real software

These are not just curiosities — programmers have used hexspeak constants for decades because they are easy to spot in memory dumps:

0xDEADBEEF — filled unallocated memory in IBM RS/6000, Cisco IOS, and classic Macs to help catch use-after-free bugs.
0xCAFEBABE — the magic bytes at the start of every Java .class file, which the JVM checks to confirm the file is valid bytecode.
0xBAADF00D — used by Microsoft’s debug heap in Visual C++ to mark freed memory.
0xC0FFEE — appears in Motorola and Java ME implementations as a debug sentinel.
0xDEADC0DE — used in Apple iOS crash reports to indicate the watchdog killed the app.

Practical use

Hexspeak is mainly for fun and for naming memorable constants, but it has real utility:

Magic number bytes in file format headers so the format is human-identifiable in hex editors.
Debug sentinels in embedded or low-level code — if you see BAADF00D in memory you know immediately what it means.
Easter eggs in firmware and bootloaders.

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